Top 10 Questions for Biochemistry Technician Interview

1. Describe the role of a buffer in a biochemical reaction. Give an example of a buffer system.

A buffer is a solution that resists changes in pH when small amounts of acid or base are added to it. Buffers are important in biochemical reactions because they help to maintain a constant pH, which is essential for the proper functioning of enzymes.

One example of a buffer system is the bicarbonate buffer system. This system consists of carbonic acid (H2CO3) and sodium bicarbonate (NaHCO3). When small amounts of acid are added to the solution, the bicarbonate ions react with the protons to form carbonic acid. Conversely, when small amounts of base are added to the solution, the carbonic acid reacts with the hydroxide ions to form bicarbonate ions.

2. Explain the principle of spectrophotometry and how it can be used to measure the concentration of a substance.

Principle of spectrophotometry

• Spectrophotometry is a technique that measures the amount of light that is absorbed by a substance. The amount of light that is absorbed is directly proportional to the concentration of the substance.
• Spectrophotometers are used to measure the absorbance of a solution at a specific wavelength. The wavelength of light that is used is chosen based on the absorption spectrum of the substance being measured.

How spectrophotometry can be used to measure the concentration of a substance

• A calibration curve is first created by measuring the absorbance of a series of solutions with known concentrations of the substance being measured.
• The absorbance values are then plotted against the corresponding concentrations.
• The calibration curve can then be used to determine the concentration of an unknown solution by measuring its absorbance and comparing it to the calibration curve.

3. Describe the process of protein purification.

Protein purification is the process of isolating a specific protein from a mixture of other proteins. The process can be divided into several steps:

• Cell lysis: The first step is to break open the cells that contain the protein of interest. This can be done using a variety of methods, such as sonication, homogenization, or chemical lysis.
• Centrifugation: The cell lysate is then centrifuged to remove cell debris and other particulate matter. The supernatant, which contains the soluble proteins, is then collected.
• Chromatography: The supernatant is then passed through a chromatography column. The chromatography column is packed with a material that binds to the protein of interest. The protein of interest will bind to the material, while the other proteins will pass through the column.
• Elution: The protein of interest is then eluted from the chromatography column using a buffer that disrupts the binding between the protein and the material.

4. Explain the difference between a denaturing gel and a native gel.

• Denaturing gels: Denaturing gels are used to separate proteins based on their molecular weight. The proteins are first denatured, which means that their native structure is disrupted. The denatured proteins are then separated by electrophoresis, which is a technique that uses an electric current to move the proteins through a gel.
• Native gels: Native gels are used to separate proteins based on their charge. The proteins are not denatured, so their native structure is preserved. The native proteins are then separated by electrophoresis.

5. Describe the role of enzymes in biochemical reactions.

Enzymes are proteins that catalyze biochemical reactions. A catalyst is a substance that increases the rate of a reaction without being consumed in the reaction. Enzymes work by lowering the activation energy of a reaction, which is the energy barrier that must be overcome for the reaction to occur.

Enzymes are highly specific for their substrates, which are the molecules that they catalyze. Each enzyme has a specific active site, which is a region of the enzyme that binds to the substrate. The active site is designed to bind to the substrate in a way that facilitates the reaction.

6. Explain the difference between a competitive inhibitor and a non-competitive inhibitor.

• Competitive inhibitors: Competitive inhibitors bind to the active site of an enzyme, which prevents the substrate from binding to the enzyme. This type of inhibition can be overcome by increasing the concentration of the substrate.
• Non-competitive inhibitors: Non-competitive inhibitors bind to a site on the enzyme that is not the active site. This type of inhibition cannot be overcome by increasing the concentration of the substrate.

7. Describe the process of DNA extraction.

DNA extraction is the process of isolating DNA from a cell. The process can be divided into several steps:

• Cell lysis: The first step is to break open the cells that contain the DNA. This can be done using a variety of methods, such as sonication, homogenization, or chemical lysis.
• Removal of proteins and other contaminants: The cell lysate is then treated with a detergent to remove proteins and other contaminants. The DNA is then precipitated out of solution using a high concentration of salt.
• Purification: The DNA is then purified using a variety of methods, such as chromatography or precipitation.

8. Explain the principle of PCR (polymerase chain reaction).

PCR is a technique that is used to amplify a specific region of DNA. The process can be divided into three steps:

• Denaturation: The first step is to denature the DNA, which means that the double-stranded DNA is separated into two single strands.
• Annealing: The second step is to anneal the primers to the single-stranded DNA. Primers are short pieces of DNA that are complementary to the ends of the region of DNA that is being amplified.
• Extension: The third step is to extend the primers using a DNA polymerase. DNA polymerase is an enzyme that synthesizes DNA from a template strand.

9. Describe the process of DNA sequencing.

DNA sequencing is the process of determining the order of the nucleotides in a DNA molecule. The process can be divided into several steps:

• Fragmentation: The first step is to fragment the DNA into smaller pieces. This can be done using a variety of methods, such as sonication or enzymatic digestion.
• Ligation: The fragments are then ligated to sequencing adapters. Sequencing adapters are short pieces of DNA that contain a known sequence of nucleotides.
• Sequencing: The DNA fragments are then sequenced using a DNA sequencer. A DNA sequencer is a machine that reads the sequence of nucleotides in a DNA molecule.

10. Explain the principles of mass spectrometry.

Mass spectrometry is a technique that is used to identify and quantify molecules based on their mass-to-charge ratio. The process can be divided into several steps:

• Ionization: The first step is to ionize the molecules. This can be done using a variety of methods, such as electrospray ionization or matrix-assisted laser desorption ionization.
• Mass analysis: The ions are then analyzed by their mass-to-charge ratio. This can be done using a variety of mass analyzers, such as a time-of-flight mass analyzer or a quadrupole mass analyzer.
• Detection: The ions are then detected using a detector, such as an electron multiplier or a photomultiplier.

Biochemistry Technicians play a crucial role in scientific research and development, ensuring the smooth functioning of laboratories and assisting in the collection, analysis, and interpretation of biochemical data.

1. Sample Preparation and Analysis

Preparing biological samples, including blood, tissues, and cells, for analysis.

• Utilizing various techniques such as centrifugation, filtration, and extraction to isolate and purify samples.
• Conducting assays and experiments to determine the composition, structure, and function of biomolecules (e.g., proteins, nucleic acids, carbohydrates).

2. Data Collection and Interpretation

Operating and maintaining laboratory equipment, such as spectrophotometers, chromatography systems, and microscopes, to collect experimental data.

• Analyzing data using statistical and computational methods to identify trends, patterns, and anomalies.
• Preparing reports, charts, and presentations to communicate findings and insights.

3. Quality Control and Assurance

Maintaining a clean and organized laboratory space, adhering to safety regulations and best practices.

• Performing regular equipment calibration and maintenance to ensure accuracy and reliability.
• Following Good Laboratory Practices (GLPs) and Standard Operating Procedures (SOPs) to ensure the quality and integrity of data.

4. Collaboration and Communication

Collaborating with scientists, researchers, and other laboratory personnel on projects and experiments.

• Communicating effectively with supervisors, colleagues, and clients to discuss results, provide updates, and troubleshoot issues.
• Participating in scientific meetings and conferences to stay informed about the latest advancements.

Preparing thoroughly for a Biochemistry Technician interview can significantly increase your chances of success. Here are some key tips and strategies:

1. Research the Company and Role

Familiarize yourself with the company’s mission, values, and research areas. Identify specific projects or accomplishments that align with your skills and interests.

2. Practice Your Technical Skills

Review the key job responsibilities outlined above and prepare examples of your experience and proficiency in each area.

3. Highlight Your Analytical and Problem-Solving Abilities

Biochemistry Technicians often face challenges in the laboratory. Showcase your ability to analyze data, identify discrepancies, and develop solutions independently or as part of a team.

4. Demonstrate Your Detail Orientation and Patience

Emphasize your attention to detail and ability to work meticulously, following protocols and safety guidelines carefully.

5. Prepare for Behavioral Questions

Behavioral questions aim to assess your soft skills and personality. Prepare for questions about teamwork, communication style, and how you handle pressure or setbacks.

6. Ask Thoughtful Questions

Asking thoughtful questions at the end of the interview shows interest and engagement. Prepare questions about the company’s research goals, career development opportunities, or specific projects you might contribute to.

7. Be Enthuasiastic and Confident

Show your passion for biochemistry and your eagerness to contribute to the team. Confidence in your abilities and a positive attitude will make a lasting impression.